Will the 2nd channel on the MB800 get close to the boost control on the MB500

Love my new MB500 especially with the boost control between 10:00 - 11:00.
It has to go back for an intermittent mute button but think I will just upgrade to an MB800.

The MB800 does not have a boost knob and a phone call with GK suggests that the 2 channels on the 800 are not identical and that you can get close to the boost tonality by using the non standard channel.

Can anyone confirm that this 2nd channel on the 800 does sound the same or very similar to the boost knob on the 500?

I can't talk in depth about it because I only had an MB800 for a short time. I started with an MB500. I was mainly running a J bass on the Boost channel for pretty much everything I was doing, basically trying to emulate the tone I was getting from my 800RB or 400RB. I was never able to get it exact but it was perfectly fine for live use IMO.

When the MB800's came around I had only had the MB500 for a very short time. I returned it and picked up an MB800 instead. The first thing I did was dialed up a similar sound to what I had on the 500 on the regular channel and the boost channel and felt they were pretty close. However, my particular MB800 had a high pitched whine that was audible at gigs so it went back. Since I felt both the MB800 and MB500 were pretty similar and had no issue with the 500, I returned the 800 and grabbed the same 500.

Thank you for this.
I've been using Ampeg heads for the most part for 20 years.
I had a brief stint with an LMII, TH500, and Walkabout.
What got me started with GK was pugging in my little 100 watt practice amp speaker out into a 2x12 cabinet. Even did a gig this way.
I wanted to better understand this whole GK grind thing so I bought a 400RB (original 1st generation with attached power cord) and an MB500.
The 400 showed up first and I really like it; it has a lot of volume for a 200 watt amp and I totally now get the GK grind thing.
The MB500 gets amazingly close to the 400RB tone and also has a boost control.
I don't know if I could tell the difference on a gig other than the 500 has way more headroom.

So, I love the 500 but it has an intermittent mute switch.
I ended up liking this amp a lot more than I thought I would (knowing that these are an easy flip).
After the last gig in a room we have played 6 times before, I REALLY like this amp so thought I'd go for the big dog with more clean headroom (my SVT 7Pro has 1kW of power so headroom was never a problem).
Just afraid that the 500 groove wouldn't be available without the boost control but I'm putting faith in you bassgododmw!
I will swap amps with RMC after this weekends gig.
A guy name Erik there is extremely cool about helping players out.

Hey all, last night I decided to try the B channel after running into this thread. What a difference, it sounded amazing! Reminded me of the old 800RB only with much, MUCH more headroom. I had the Gain-B at about 1:30 and it was growling...very tight mid-rich sound, what I've been looking for out of the MB800! Thank you, I had wrongly assumed both channels were the same, they might want to re-label those...

Its funny that you say this.
Last night at rehearsal I used my MB800 and thought it sounded different than the boost control from the MB500 I returned last week.
It could also just be in my head.
FWIW I think I like the MB500 boost better but not enough to change.
The weight and depth of the notes are stronger with the MB800 even at low volumes.

Very small differences in knob setting make a pretty big difference sonically. I set mine where it would just barely break up on the loud notes. It's a whole different animal if you just back it down to 12:00 from 1:30. This thing just CRUSHed last night!

No, I have found the same with the MB800.
Still think the the MB500 boost control sounds different (and better) than the pre/master of the 800 and I have been experimenting with different gain structures between channel B / B Master / and Main Master.
OTOH, the notes have more weight, girth and definition.

I did thoroughly compare the the RB400 vs the MB800 and approx the same quiet volume and they sounded very similar.
Last night I thought the 400 was slightly nicer although I could change my mind today.

The MB800 vs. my memory of the 1001RB-II is no contest. I much prefer the MB800. A very unscientific comparison for sure!

Are you testing at gig volume?

I would love to hear your thoughts on the gain structure testing you're doing. My settings came from a brief 'play-around' before the band got here. I know at the gig it will change, it always does.

Click to expand...

Great point as I am not testing at gig volume.
In reality the 400RB probably does not have quite enough clean headroom to gig with my 2x12.
This is a guess as I haven't actually tried, but have come home from jobs with the setting in tact on the MB and the gig volume wasn't so much louder but beefier, cleaner and with tons more headroom.
Totally unfair test at volume as it's 200 watts vs. 800.

Now here's a sad/funny thing only of interest to me probably...I was just doing a search about the B channel on the MB800. I totally forgot about posting up there. ^ I ran my MB800 on the B channel, until some power issues at the club made it jump back to channel A. (if you don't know, it resets to 'A' every time it powers down) So I started running it on the A channel for the last 8 months. Some experimentation last night led me back to the B channel having more of the 'Boost' sound GKs are famous for.